Power MOSFETs with trench gate structures are widely used for their efficient performance due to their low ON-state resistance (RDSON). U.S. patent application No. U.S. Ser. No. 11/930,380 (filed on Oct. 31, 2007) disclosed a trench MOS-gated device that provides a constant RDSON. See also U.S. Pat. No. 5,973,367 (issued on Oct. 26, 1999), which disclosed a double-diffused vertical MOSFET in which the gates therein are formed in a trench and separated by a P-doped region. Both of the above patent documents are incorporated herein by reference.
This Discussion of the Background section is for background information only. The statements in this Discussion of the Background are not an admission that the subject matter disclosed in this section constitutes a prior art to the present disclosure, and no part of this section may be used as an admission that any part of this application, including this Discussion of the Background section, constitutes prior art to the present disclosure.